This disclosure generally relates to a biological fluid processing system and method thereof. More specifically, this disclosure relates to a system and method for a therapeutic exchange procedure that exchanges at least one constituent component, such as a blood component, from a withdrawn biological fluid, such as whole blood, from a patient with one or more replacement fluids that are infused to the patient.
Blood processing systems and methods that relate to a therapeutic exchange procedure typically withdraw a biological fluid, such as whole blood, from a patient. The biological fluid, such as whole blood, may be directed to a separator, such as a centrifugal or membrane assembly, for separation of at least one constituent component, such as at least one blood component, for example, red blood cells, plasma and/or platelets, from the remaining blood components. Depending on the procedure, certain separated constituent components may be retained by the system and not returned to the patient. The remaining separated constituent components may be returned to the patient together with one or more fluids to replace the constituent retained by the system. The particular separated constituent that is not returned to the donor may depend on the specific medical needs of the patient. For example, one type of therapeutic exchange procedure is a red blood cell exchange procedure that removes a quantity of separated red blood cells from the withdrawn whole blood of a patient and returns to the patient at least one replacement fluid, such as fresh red blood cells from a healthy donor, an additive solution or other fluid, along with the remaining separated blood components.
In a therapeutic exchange procedure, it is generally desired to maintain a patient's fluid balance such that the difference between the amount of removed fluid and replaced fluid is within a desired range. However, in a red blood cell exchange procedure it may also be desired to monitor the hematocrit of the removed red blood cells so as to avoid the patient receiving too many or too few replacement red blood cells. For example, during a red blood cell exchange procedure, if the removed red blood cells have a hematocrit that is higher than the replaced red blood cells then the patient receives too few red blood cells. If the removed red blood cells have a lower hematocrit than the replaced red blood cells, then the patient receives too many red blood cells.